Patent application number | Description | Published |
20080309467 | DRIVING APPARATUS OF MOVER - A driving apparatus drives a mover arranged for feedback of a touch panel. A reference voltage generation unit generates a reference voltage having a signal waveform to be applied to the mover. A pulse modulator generates a PWM signal of which duty ratio is controlled by feedback so that a feedback voltage corresponding to a drive voltage to be applied to the mover approaches the reference voltage. A switching element of the DC/DC converter is turned ON/OFF by a PWM signal from the pulse modulator, so that an output voltage of the DC/DC converter is controlled, and a drive voltage corresponding to the output voltage is applied to the mover. | 12-18-2008 |
20090039234 | LIGHT-EMISSION CONTROL CIRCUIT - A light-emission control circuit may include n light-emitting devices, where n is an integer equal to or greater than 2; a light guide plate which causes light emitted by the n light-emitting devices to reach the entirety of the back of a liquid crystal panel; a measuring unit for measuring a luminance of the entirety of the n light-emitting devices operating in the liquid crystal panel; and a control unit for comparing the measured luminance with a predetermined value and controlling the luminance of the n light-emitting devices, based on a result of comparison, wherein the n light-emitting devices are attached to a side of the light guide plate, and the measuring unit is attached to an opposite side of the light guide plate. | 02-12-2009 |
20090072626 | POWER SUPPLY APPARATUS HAVING SWITCHABLE SWITCHING REGULATOR AND LINEAR REGULATOR - A control circuit is provided in which two power sources can be efficiently switched, for a power supply apparatus provided with a step down switching regulator and a linear regulator. A PWM controller generates a pulse width modulation signal with which a duty ratio is controlled so that output voltage of the switching regulator approaches a predetermined reference voltage. A compulsory OFF circuit monitors a switching voltage, and when a first threshold voltage is exceeded, switches a synchronous rectifier transistor OFF. A minimum ON time setting circuit limits the duty ratio of the pulse width modulation signal, so that ON time of the switching transistor is longer than a predetermined minimum value. A selector circuit monitors an error voltage, and when a predetermined state continues for a predetermined first period, puts the linear regulator in an operating state, and the step down switching regulator in a halt state. | 03-19-2009 |
20090096382 | DRIVE CONTROL CIRCUIT, EMISSION CONTROL CIRCUIT, COMMUNICATION APPARATUS AND DRIVE CONTROL METHOD - A drive control circuit sends out pulse signals of various pulse signals so as to control the light emission amount and luminance of LEDs by gradually increasing and decreasing the pulse width in predetermined cycles during predetermined periods based on parameters supplied from an LED drive controller that determine a first emission control processing period, a second emission control processing period, first to fourth slope periods and the like. The tone of an emitted color realized by a plurality of LEDs is controlled by synchronizing the periods of time of light emission control processings. | 04-16-2009 |
20090096389 | DC/DC CONVERTER - A control circuit of a DC/DC converter is provided for supplying a driving voltage to a light emitting element. A hysteresis comparator compares a detection voltage that corresponds to the output voltage of the DC/DC converter with two threshold voltages. If the detection voltage is smaller than the lower threshold voltage, the hysteresis comparator outputs a comparison signal at the low level. Otherwise, the comparison signal is set to the high level. The switching control unit uses the comparison signal as a reference. The switching control unit instructs the switching transistor of the DC/DC converter to perform the switching operation during a period when the comparison signal is at the low level. Otherwise, the switching operation is suspended. The control circuit inhibits light emission of the light emitting element during a period when the comparison signal is at the low level. Otherwise, the control circuit permits the light emission. | 04-16-2009 |
20090102435 | CONTROL CIRCUIT AND METHOD FOR CAPACITOR CHARGING CIRCUIT - An output voltage monitoring circuit monitors an output voltage of a capacitor charging circuit. A first sample-and-hold circuit samples and holds a voltage of a connection point of a primary coil of a transformer and a switching transistor. A first monitoring comparator compares output of the first sample-and-hold circuit with a predetermined first reference voltage. When the output of the first sample-and-hold circuit exceeds the first reference voltage, a signal processor executes predetermined signal processing. The first sample-and-hold circuit starts a sampling period after a predetermined first time has elapsed after the switching transistor is turned OFF. When a voltage drop across a detection resistor reaches a third reference voltage, the first sample-and-hold circuit ends the sampling period. | 04-23-2009 |
20090108178 | CURRENT DETECTION CIRCUIT - A current detection circuit detects photoelectric current that flows through a phototransistor, and outputs a current, which is proportional to the photoelectric current, via an output terminal. An input-side transistor is a PNP bipolar transistor, and is provided on a current path for the phototransistor. Output-side transistors are PNP bipolar transistors. The base terminals thereof are connected to that of the input-side transistor so as to form a common base terminal, and the emitter terminals thereof are connected to that of the input-side transistor so as to form a common emitter terminal, thereby forming a current mirror circuit. Each of first switches is provided between the collector of the corresponding output-side transistor and an output terminal. Each of second switches is provided between the collector of the corresponding output-side transistor and the ground terminal. A control unit controls the ON/OFF operations of the first switches and the second switches. | 04-30-2009 |
20090108827 | UNDER VOLTAGE LOCK OUT CIRCUIT AND METHOD - An under voltage lock out circuit which monitors an input voltage and executes a predetermined sequence when the input voltage satisfies a predetermined condition may include a voltage comparison unit which compares the input voltage and a predetermined threshold voltage, and outputs a comparison signal; a logic circuit which receives the comparison signal output from the voltage comparison unit and a start-up signal instructing start-up of an equipment mounted with the under voltage lock out circuit, and asserts a sequence control signal when start-up is instructed by the start-up signal in a state the input voltage is higher than the threshold voltage; and a sequence circuit which executes a predetermined sequence when the sequence control signal is asserted, wherein the predetermined threshold voltage is switched according to the sequence control signal. | 04-30-2009 |
20090129768 | CONTROL CIRCUIT FOR SELF-EXCITATION DC/DC CONVERTER, LIGHT EMITTING DEVICE USING SUCH CONTROL CIRCUIT, AND ELECTRONIC DEVICE - A switching transistor is connected to the primary coil of a transformer. A first resistor is provided such that one end thereof is connected to the switching transistor, and the other end thereof is grounded. A first voltage comparator compares a first detection voltage with a first threshold voltage. A second voltage comparator compares a second detection voltage with a second threshold voltage. A switching control unit controls the ON/OFF state of the switching transistor according to the output signals of the first voltage comparator and the second voltage comparator. A first electrode pad through a fourth electrode pad are provided to the respective nodes of the switching transistor and the first resistor. | 05-21-2009 |
20090200962 | POWER SUPPLY APPARATUS - In a power supply apparatus for performing constant current driving of a light emitting diode which is a load circuit, a constant current circuit is disposed on a path for driving the load circuit. A charge pump circuit which is a voltage generating circuit outputs a driving voltage to the light emitting diode. A monitoring circuit monitors the voltage across the two ends of the constant current circuit. This monitoring circuit includes a voltage source which generates a threshold voltage that follows the fluctuation of the voltage at which the constant current circuit can operate stably, compares the voltage across the two ends of the constant current circuit and the threshold voltage generated by the voltage source, and outputs a comparison result Vs to a control unit. The control unit controls the charge pump circuit on the basis of the output of the monitoring circuit. | 08-13-2009 |
20090242734 | CURRENT DETECTION CIRCUIT, PHOTORECEIVER USING THE SAME, LIGHT EMISSION CONTROL DEVICE, AND ELECTRONIC DEVICE USING THE SAME - A first transistor may be provided on a current path of a photo transistor. The bias current path may include a bias switch and a first bias resistor connected in series and is provided in parallel with a main current path including the phototransistor. A second transistor may configure a current mirror circuit with the first transistor, and generates second current formed by multiplying the first current flowing in the first transistor by a predetermined factor. The second current is charged in the charging capacitor and converted into a voltage. The bias current path turns on prior to the start of light reception of the phototransistor and turns off after a predetermined period has elapsed from the start of light reception of the phototransistor. | 10-01-2009 |
20090273327 | POWER SUPPLY DEVICE, ELECTRONIC DEVICE USING THE SAME, AND SEMICONDUCTOR DEVICE - A linear regulator is provided which stabilizes an input voltage based on a reference voltage source that generates a reference voltage, and the reference voltage generated by the reference voltage. An output voltage of the linear regulator is supplied as a power supply voltage of a switching controller and the reference voltage source. The linear regulator is configured to enable switching of a regulation mode in which voltage is outputted according to the reference voltage, and a bypass mode in which an input voltage is outputted as it is, with no relation to the reference voltage. When a power supply apparatus is started up, during a time period until the input voltage reaches a predetermined threshold voltage, the linear regulator operates in the bypass mode, and when the input voltage exceeds the threshold voltage, operates in the regulation mode. | 11-05-2009 |
20100066336 | POWER CONTROL CIRCUIT - A control circuit | 03-18-2010 |
20100225250 | DRIVE CIRCUIT OF DC/DC CONVERTER, LIGHT EMITTING APPARATUS AND ELECTRONIC DEVICE USING THE SAME - A drive circuit controls the on/off state of a switching transistor of a DC/DC converter. A first resistor is provided on a path of current flowing through a primary coil of a transformer connected to the switching transistor, and one end of the first resistor is grounded. A second resistor is provided on a path of current flowing through a secondary coil of the transformer, and one end of the second resistor is grounded. A switching controller turns off the switching transistor when a first detection voltage exceeds a first threshold voltage and, turns on the switching transistor after lapse of predetermined delay time since a second detection voltage exceeds the second threshold voltage. | 09-09-2010 |
20110006694 | DC/DC CONVERTER CONTROL CIRCUIT, AND POWER SUPPLY APPARATUS, LIGHT EMITTING APPARATUS AND ELECTRONIC DEVICE USING THE SAME - A control circuit is provided for a separately excited DC/DC converter which directly monitors output voltage to detect a short-circuit state, and performs overcurrent protection. A switching controller of the control circuit controls a switching operation of a switching transistor of the separately excited DC/DC converter. A voltage comparator compares the output voltage and a threshold voltage, to detect the short-circuit state. After a predetermined start-up time has elapsed after beginning start-up of the separately excited DC/DC converter, when the voltage comparator detects the short-circuit state, the switching controller halts the switching operation of the switching transistor, and makes detection of the short-circuit state by the voltage comparator non-operative before elapse of the start-up time. After detecting the short-circuit state and halting the switching operation of the switching transistor for a predetermined halt time, the switching controller begins start-up of the separately excited DC/DC converter once again. | 01-13-2011 |
20120203484 | BATTERY FUEL GAUGE CIRCUIT - A detection circuit is mounted on an electronic device having a communication function, including at least a battery, a CPU, and a communication unit, and is configured to detect the remaining battery charge. An A/D converter performs sampling of a magnitude of a current I | 08-09-2012 |
20140313793 | POWER DELIVERY DEVICE, AC ADAPTER, ELECTRONIC APPARATUS AND POWER DELIVERY SYSTEM - The PD device includes: a DC/DC converter disposed between an input and an output; a primary-side controller configured to control an input current of the DC/DC converter; and a secondary-side controller connected with AC coupling to the output, and configured to feed back electric power information of the output to the primary-side controller. The primary-side controller varies an output voltage value and an available output current capacity of the DC/DC converter by controlling the input current on the basis of the electric power information fed back from the secondary-side controller. | 10-23-2014 |